A 3D-EPI sequence was implemented and its use
investigated for high-resolution fMRI at 7T. Comparisons with conventional 2D-EPI
reveal considerably increased sensitivity for isotropic 2.5mm resolutions and
higher. Results of a whole-brain activation study at 1mm3 resolution at TR=3s
are presented. The ability to apply parallel acceleration along two dimensions
allows substantial time savings and protocols with >100 slices to remain
compatible with fast fMRI. The SAR and gradient limitations or 2D-EPI are
removed entirely, and the often compromised parallel reconstruction of 2D-EPI
in regions of low SNR considerably improved. The results strongly suggest that
3D-EPI should be chosen over 2D at high field.